The problem with current SIM/smart card solutions and especially the ISO7816 interface is that the currently existing smart cards have only 3 “free” contact pins and there will be several applications that would need to interface the secure smart card element including e.g. USB (Universal Serial Bus) & NFC (Near Field Communication) (e.g. payment/ticketing) applications.
The ISO/IEC ISO7816-3 specification of 1997 in English is downloadable from the internet, while the specification ISO/IEC ISO7816-4 has been withdrawn.
It is known in the art to provide devices with combined interfaces capable of receiving different kinds of memory cards as it is e.g. disclosed in U.S. Pat. No. 6,612,498. This document discloses a mobile station (MS) that includes an interface card slot (SLOT) to which it is possible to connect either an MMC-card or a small SIM-card. A separate adapter the size of an MMC-card is used to connect the small interface card, or, in addition to the first contact pins for use of an MMC-card, second contact pins for use of an SIM-card are arranged to the interface card slot. The operating voltage of the interface card is selected to fit the currently used interface card.
It is also known in the art to use a switching circuitry to receive different memory cards in a common connector, wherein a device can arbitrate between different memory card interface modes. Such an electronic device capable of receiving a number of different memory cards is e.g. disclosed in the U.S. Pat. No. 6,857,038. This document discloses a common connector for memory cards and a switching arbitration method for the shared pins of the connector, i.e., a common connector which allows many different types of memory cards to be inserted in and fixed at different times.
It is known to provide devices which are able to receive different kinds of memory cards such as e.g. SD (Secure Digital), MMC (Multi-Media Card), ISO7816 SIM cards (subscriber identification means cards) or SM (smart media).
Especially in case of SIM cards of mobile terminals with a set format and a limited number of connection contacts, the standard ISO7816 interface must be retained so that operators can issue new SIM cards that will still work in older terminals. That is, it is a requirement that the existing interface must be retained for all the other non-phone applications that still use the same interface connections. As there are several different proposals for using the few remaining pins there is a conflict between these several applications to use the same contacts for differing signal levels and protocols.